Dr. Tsai's research deals with neural circuit changes that result in abnormal sensitivity or gain regulation in epilepsy. Such changes reflect an imbalance between excitatory and inhibitory drives, leading to neural hyperexcitability, a hallmark of epilepsy. Since gain control is a fundamental property of the brain, one would expect that alterations in gain control mechanisms would have widespread manifestation in functional domains (e.g., different sensory modalities) and in other developmental disorders. Indeed, there is mounting evidence that autism spectrum disorders and schizophrenia show an imbalance between excitation and inhibition. Tsai uses the framework of gain changes to understand sensory and cognitive changes in these disorders.

Tsai is currently using the human visual system as a model to look for evidence of gain changes in patients with idiopathic generalized epilepsies, many of whom are found in the pediatric population. He uses high-density source-imaged EEG to study visual evoked potentials, fMRI to study visual activity in deep brain structures, and psychophysics to study perceptual correlates of these changes.